Brake mechanism



Sept. 13, 1932. R s. SANFORD 1,877,597

' BRAKE MECHANISM Fil'ed MaI'Ch 20, 1929 IN VEN TOR.

ATTORNEY Patented sept. 13, 1932 ROY SELDEN SANFORD, or SOUTH COMPANY, F SO'TH BEND,

BEND, NDIANA, ASSIGrNOR TO BENDISI BRAKE NDIANA, A. CORPORATION OF ILLINOIS BRAKE MECHANSMI Application led March 20, 1929. Serial No. 348,515.

My invention relates to improvements in brake mechanism and particularly to brakes for the road wheels of motor vehicles.

More specifically1 the invention resides in 5 brake mechanism provided with an improved servo responsive tothe rotation of the brake drum, improved means for actuating the servo into engagement with the drum and improved operating connections between the servo and the remaining brake mechanism for urging the same into braking engagement with the drum.

An object is the provision, in brake mechanism of the character set forth and having a rotatable brake drum,'of retarding mea-ns arranged to be moved into frictional engagementtherewith and a servo shoe disposed within said retarding means and adapted to be independently moved into engagement with the drum, said servo shoe being coupled with the retarding means to urge it into frictional engagement with the drum.

' The retarding means preferably1 embodies a plurality of brake Vshoes and a servo shoe disposed entirely within oneof them. The

shoe within which the servo shoe is arranged is here shown as a floating brake shoe pivotally articulated with a second brake shoe to apply both brake shoes to the drum.

Power multiplying connections'couple the servo shoe with the brake shoes to brake them into engagement with the drum in either direction of drum rotation. The servo shoe-and the brake shoes are constrained away from the drum by suitable springs and adjustable tracted positions of such shoes.

The servo shoe is supported to swing from one end by linkage which embodies in part operating means for urging the brake shoes for engagement with the drum and the servo shoe is automatically angularly adjustable upon this linkage to vary its normal 4position with respect to the drum to take up for wear.

Other objects and meritorious advantages of my invention will more fully appear from the following description of the illustrative embodiment shown in the accompanying -drawing and defined in the appended claims.

1n the drawing:

devices are provided to determine the re- Fig. 1 is a vertical sectional view through a brake drum and brake mechanism embodying my invention.

lFig. 2 is a fragmentary plan the brake mechanism.

Fig. 3 is a fragmentary sectional view showing a modified form of construction of the servo operating mechanism.

My invention is illustrated in the drawing as embodied in a construction having a backing plate 9, a brake drum 10, provided with suitable lining 12, and wherein are arranged brake shoes 14, 16, and 18, adapted to be moved into frictional braking engagement with the drum. rl`hese shoes carry suitable brake lining Q0. Shoes 16 and 18 are mounted upon a fixed pivot 22 and shoe 1li is pivotally articulated at Qi with shoe 16. Adjustable eccentric devices 26 are provided to determine the idle position of the shoes 16 and 18. A spring 28 holds the shoe 16 against the eccentric 26, and spring 30 holds the shoes 1-1 and 18 inwardly away from the drum and toof aportion of j ward the operating cam.

The shoe 14 is provided with an elongated circumferential opening 39. wherein is arranged a servo shoe 3st one end of which is pivotally connected by a link 36 with a cam 38, which cam is interposed between the adjacent ends of the shoes 1st and 1S to spread them apart'against the drum. r1`he cam is shown as provided with projecting ears 39 between which the end of the link is received and pivotally articulated by a pin 40, and the end of the shoe 34 is shown as provided with projecting ears L12 between4 which the opjjioi-:ite end of the link is disposed and pivotally articulated by a pin 4A. In Fig. Q a spring meinber 46 is shown as arranged upon the. pin or i bolt 4A andt-ensioned by a nut -18 so that the connection between the servo shoe and the link is an adjustable frictional connection whereby the angularity of the link and shoe may be adjustably varied.

The shoe 3411215 its opposite endheld away from the drum by a spring 50 and the shoe itself is moved into engagement with the drum by a cam 52 carried by a shaft 51. The shoe 14 is'of channel shape so that the shoe 3iarranged therein and the shaft -l of the operating cam is suitably supported in the backing plate.

The cam 38 is pivotally'supported upon a link 56 pivoted at 58 to the backing plate and provided with an angular portion 60 terminating in a pintle 62 upon which the cam is journalled. A key 64 is shown to hold th-e cam in place. The cam is provided with side flan es 66 which engage upon opposite sides of tie reduced end portions 68 of the shoes 14 and 18 thereby holding the shoes in alignment. These reduced end portions 68 take the vthrust of the cam in' spreading the shoes apart. A

. In Fig. 3 I have illustrated a slightly modilied type of constructiony wherein the idle position of the shoe 34 is determined in part by an adjustable eccentric 70 `which extends through and is mounted in the backing plate and which engages the inner face of the shoe 34 adjacent its free end. The spring 50 in this construction is connected to the shoe 34 drum by between the eccentric 7 0 and the operating cam 52. Otherwise the mounting of the shoe d is similar to that shown in Fig. 1. The shoe 14 is, of course, cut away to accommodate for the link 36 as it would be necessary to insure its operation.

In the operation of the device the servo shoe 34 is moved into engagement with the the cam 52 and, rotating with the drum, actuates the cam 38 to spread the ends of shoes 14 and 18 into engagement with the drum. Shoe 14 in turn actuates shoe 16 and the device responds to rotation of the drum in either direction and the mounting of.

the cam 38 is such that it accommodates itself to such operation or to wear of parts.

The connection between the link 36 and the servo shoe 34 is of such a character that the shoe has a tendency to swing about the ypivot 40 so that in the construction shown in Fig. 1 the pivoted end of the-shoe will not. drag upon the drum. It may also be mentioned that the spring 50 is a relatively weak spring insuiiicient to overcome the frictional engagement of the shoe with the link. In Fig. 3'

there is, of course, no tendency for the pivoted end of the shoe 34 to drag upon the drum when the shoe is' in the idle position because spring 50 is connected with the shoe between the eccentric and the cam 52.

Serial No. 149,615, filed Novemsaid pair of brake shoes arranged within the drum to be moved thereagainst, a servo shoe arranged within one of said shoes and coupled with the other shoe to urge it against the drum upon actuation of the servo shoe by the drum, and means for moving said'servo shoe into engagement with the drum.

4. In brake mechanism, a brake drum, a pair of brake shoes arranged within the drum to be moved thereagainst, a servo shoe arranged within one of said shoes and coupled with both of them to urge them against the rum upon rotatable actuation of the servo shoe by the drum, and means for moving said servo shoe into-engagement with the drum.

5. In brake mechanism, a brake drum, a

plurality of brake shoes arranged Within the 4 drum, a servo shoe arranged within one of opening, and coupled with one of the brake shoes to .urge the same into engagement with the drum.

7. In brake mechanism, a brake drum, a

brake shoe adapted to exert a braking force thereon, a servo shoe arranged wholly within saidV shoe and adapted to be moved into engagement withthe drum, said servo shoe.

coupled with the first mentioned shoe to urge the same into engagement with the drum as the servo shoe is actuated thereby.

8. In brake mechanism, a brake drum, a brake shoe arranged to exert a braking force thereon, said shoe provided with a circumfer- This application is a continuation in part of ential opening, a servo shoe arranged within opening, a cam to move the servo shoe into engagement with the drum, andv a cam coupled with the servo shoe to be actuated thereby to urge said first mentioned shoe into engagement with the drum.

9. In brake mechanism, a brake drum, a pair of brake shoes arranged therein yto be' moved into braking engagement therewith, a servo shoe arranged within one of the brake shoes, means for moving the servo shoe into engagement with the drum, a cani arranged to actuate both brake shoes, and means coupling the cam with the servo shoe to be actuated thereby to urge the brake shoes into engagement with,the drum.

10. ln brake mechanism, a brake drum, a plurality of brake shoes arranged to be moved thereagainst to eXert abraking torce thereon, a` servo shoe arranged within one brake Shoe, means operable to move the servo shoe into engagement with the drum, a cam arranged to urge two 'of the brake shoes into engagement with the drum, and means coupling the cam with the servo shoe whereby the cam is actuated to urge said two shoes against the drum.

11. Brake mechanism comprising, in combination, a brake drum, a brake shoe operable to engage the drum, a servo shoe arranged within the brake shoe and adapted to be moved against the drum, said servo shoe connected with the brake shoe to u'rge it against the drum in either direction of travel of the servo shoe with the drum.

1Q. Brake mechanism comprising, in combination, a brake drum, a plurality of brake shoes arranged within the drum, a servo shoe of less length than any one of said plurality of shoes and arranged within one of them and adapted to be moved into engagement with the drum and means connecting the servo shoe with said plurality of shoes to apply them to the drum.

13. Brake mechanism comprising,l in combination, a brake drum, an expansible friction device within the drum having separable ends adapted to be spread apart to apply said friction device to the drum, a servo shoe arranged within said friction device and being of substantially less length and adapted to be urged against the drum and coupled with the separable ends of said friction device to expand it against the drum.

14. Brake mechanism comprising, in combination, a brake drum, a brake shoe arranged therein to be moved against the drum, a serv shoe arranged within the brake shoe to be moved against the drum, and power multiplying means'connecting the servo shoe with the brakeshoe to apply it to the drum.

15. ln brake mechanism, a brake drum, a pair of articulated brake shoes anchored at one end within the drum, a servo shoe arranged within one of the brake shoes to be moved into engagement with the drum and coupled with the .floating shoe of said pair of shoes to urge both of them against the drum.

16. Brake mechanism comprising, in combination, a brake drum, a retarding device adapted to be moved into engagement with the drum, a servo shoe pivotally supported to be swung into engagement with the drum and adjustable angularly with respect to its support to vary the arc of its normal position with respect to the drum, means oper 65 able to move said servo shoe into engagement with the drum, and means disconnectedly coupling the servo shoe with the retarding device to actuate it into engagement with the drum.

17. Brake mechanism comprising, in combination, a brake drum, a brake shoe arranged to be moved into engagement there with, a servo shoe arranged within the brake shoe and pivotally supported at one end tor movement into engagement with the drum, a spring constraining the opposite 'end of the servo shoe away from the drum, a part arranged between the pivoted end and the spring constrained end of the shoe to determine its retracted position with respect to the drum.

1.8. Brake mechanism comprising, in combination, a brake drum, a brake shoe arranged to be moved into engagement therewith, a servo shoe arranged within the brake shoe and pivotally supported at one end for movement into engagement with the drum, a part arranged in proximity to the opposite end ot the servo shoe to determine its retracted position with respect to the drum and adjustable to vary said position, a spring engaging said shoe between said pivoted end and said part constraining the shoe away from the drum.

19. ln brake mechanism, a lbrake drum, a. pair of brake shoes arranged within the drum to exert a braking force thereon, a servo shoe arranged within one of said brake shoes, means for moving the servo shoe radially into engagement with the drum, and means coupling the servo shoe with the brake shoes whereby the servo shoe urges the brake shoes against the drum.

20. In brake mechanism, a brake drum, a brake shoe adapted to exert a braking force thereon, said brake shoe provided with an opening therethrough, a servo shoe arranged within said opening, means for actuating said servo shoe into engagement with the drum, and means coupling the servo shoe with the irst mentioned shoe to urge the same into engagement with the drum as the servo shoe is actuated thereby.

21. In brake mechanism, a brake drum, a brake shoe arranged to exert a braking force thereon, said shoe provided with al circumferential opening, a servo shoe arranged within said opening, a cam to move the servo shoe into engagement with the drum, and a second cam coupled with the servo shoe to be actuated thereby to engage the end of the first mentioned shoe to urge it against the drum.

22. In brake mechanism, a brake drum, a plurality of brake shoes arranged to be moved thereagainst to exert a braking force thereon, one of said shoes provided with an elongate opening, a servo shoe arranged within said opening,-a cam operable to move the servo shoe against the drum, a second cam posi-l tioned between the separated ends of two of the brake shoes, and a link connecting the servo shoe with the second cam to actuate the cam to urge said two shoes against the drum.

23. In brake mechanism, a brake drum, a plurality of brake shoes having separated ends arranged within the drum, one of said shoes provided 'with an aperture arranged in proximity to said separated ends, a servo shoe arranged within said aperture, a cam operable to move the servo shoe into engagement with the drum, a second cam disposed between the separated ends of said shoes, and' means connecting the servo shoe with the second cam to actuate the same to urge the shoes against the drum.

24. In brake mechanism, a brake drum, three pivotally articulated segmental shoes, one being a floating shoe and substantially shorter than the remaining two shoes and having an end portion separated from an end of v one of the other shoes, said floating shoe havingan elongate circumferential opening, a servo shoe positioned within said opening to engage the drum, means for actuating the servo shoe into engagement with the drum, a cam positioned between the lioating shoe and a shoe adjacent thereto, and means connecting saidcam with the servo shoe whereby upon rotatableactuation'thereof with the drum the cam is actuated to move the shoes engaged thereby against the drum.

Y 25. Brake mechanism comprising, in combination, a brake drum, retarding means arranged within the drum to be moved into env gagement therewith, a servo shoe having an arcuate llength of less than 90 arranged within the retarding means and adapted to be l moved into engagement with the drum and connected with the retarding means to urge it against the drum as the servo shoe is actuated b the drum.

26. rake mechanism comprising, in combination, a brake drum, a retarding device adapted to be moved into engagement with the drum, a servo shoe arranged within said j retarding device and adapted to be moved into engagement with the drum and connected with said retarding device to move it into engagement with the drum in either direction of rotation of the drum.

27. Brake mechanism comprising, in combination, a brake drum, brake shoes having separable ends arranged within the drum. to be moved thereagainst, a cam between said separable ends to expand the shoes against the drum, a servo shoe arranged within one of the shoes to be moved against thedrum, a link pivotally connecting the servo shoe with the cam to actuate it to urge the brake shoes against the drum in either direction of rotation of the drum.

28. Brake mechanism comprising, in combination, a brake drum, a brake shoe arranged therein to be moved against the drum, a servo shoe pivotally supported'witbin the brake drum, means operable to move the servo'shoe into engagement with the drum, and means actuated by the servo shoe disconnectedly coupled with the retarding device to urge the same into engagement with the drum.

30. Brake mechanism comprising, in combination, a brake drum, a retarding device adapted to be moved into ,engagement with the drum, a servo shoe, means supporting the servo shoe for swinging movement into engagement with the drum automatically adjustable to vary the normal position of the servo shoe with respect to the drum, means operable to apply the servo shoe to the drum, and means disconnectedly coupling the servo shoe with the retarding device to apply it to the drum.

3l. Brake mechanism comprising, in combination, a brake drum, expansible retarding means arranged therein and having spaced apart ends, and applyingV mechanism including a servo shoe, a pivotally supported link, a cam pivotally supported upon the link between the ends of said retarding means and an operating connection between the servo shoe and that end of the cam adjacent to the periphery of the drum.e f

32. Brake mechanism comprising, in com-l bination, a brake drum, a friction member supported therein, a servo shoe therein, a rock member supporting the servo shoe for movement into engagement with the drum, said rock member being automatically angularly adjustable with respect to the shoe to take up for wear of the shoe, and means supporting the rock member for actuating the friction member. j

In testimony whereof, I, ROY S. Samoan, sign this specilication.

ROY SELDEN SANFORD. 

